Does tryptophan in turkey really make you sleepy?

It’s an annual tradition every 4th Thursday in November: After acknowledging all that you’re grateful for—family, friends, nature’s beauty, good health —you tuck into the abundant turkey feast laid out on your groaning Thanksgiving table.

Then… the post-meal fatigue hits, and you’re ready for a nice nap.

Is the bird to blame for your food coma? Does turkey really make you sleepy? Or is this a post-Thanksgiving myth that we perpetuate to avoid doing the dishes? Let’s set the record straight.

Does turkey actually make you sleepy?

Most people think that turkey makes you sleepy because it contains the amino acid tryptophan. Tryptophan is one of 20 naturally occurring amino acids found in protein-rich foods (including turkey) and is involved in our body’s production of the neurotransmitter serotonin, a mood regulator. Serotonin is also a precursor to the sleep-associated hormone melatonin. Both serotonin and melatonin work to relax our bodies and encourage sleep.

So if tryptophan is a precursor to serotonin, which is a precursor to melatonin, which is tied to sleep, then the tryptophan in turkey must be the reason we’re knocked out after Thanksgiving dinner. Right?

Well, not exactly.

First, what is tryptophan?

Tryptophan is considered an essential amino acid, meaning we have to get it through our diets because our bodies don’t produce it. Essential amino acids are often referred to as the building blocks for protein synthesis.

Tryptophan is important for various bodily functions, including the synthesis of proteins, the production of niacin (a B vitamin), and the formation of neurotransmitters like serotonin. Serotonin is a neurotransmitter that plays a crucial role in regulating mood, sleep, appetite, and other physiological processes.

Tryptophan is commonly associated with the drowsiness that some people experience after consuming a large meal, such as a Thanksgiving feast that includes turkey. However, it's important to note that while tryptophan is present in turkey, it is also found in many other protein-rich foods. The "Thanksgiving sleepiness" is more likely a result of a combination of factors, including the consumption of a large meal, carbohydrates, and possibly alcohol, rather than tryptophan alone. But we will get further into that later.

Does tryptophan in turkey make you sleepy?

After eating your turkey dinner, tryptophan and the other amino acids found in protein-rich foods circulate through the bloodstream. In order for tryptophan to cross the blood-brain barrier and begin converting to serotonin, it needs a particular carrier protein to shuttle it across.

The same carrier protein that transports tryptophan also transports several other amino acids into the brain. Essentially, the amino acids all compete for space on the same carrier protein “shuttle” to cross the blood-brain barrier. This results in a limited amount of tryptophan actually making it into the brain to be converted to serotonin — and an even smaller amount that gets synthesized into melatonin.

So tryptophan doesn’t make you sleepy?

It does, but in greater amounts—and in a pure pill form (where it’s not competing with other amino acids to get to the brain).

Studies have shown that supplementing with 1 to 5 grams of tryptophan may help with sleep, but findings are inconsistent. Many adults who take tryptophan supplements to help with sleep take 5 grams. By comparison, a 6-oz turkey breast contains about 400 milligrams of tryptophan. So you’d need to eat around 12 servings of turkey to equal the tryptophan in a supplemental dose. That would entail quite a few trips to the buffet table.

Why does it seem like turkey makes you sleepy?

Feeling tired after Thanksgiving dinner is a common experience for many people, and there are a few reasons that can contribute to this sensation. There are several other reasons you might be tired after your Thanksgiving meal and turkey could be the scapegoat for the sleepiness.

• Daylight Savings: Since resuming standard time a few weeks earlier, the sun sets in the late afternoon across much of the northern hemisphere. Melatonin’s main role is to convey information concerning the daily cycle of light and darkness to body structures, and that includes making you drowsy when it gets dark. Much as you may want to watch another few hours of football, your body’s circadian rhythm is telling you it’s time to get some sleep.
• Food coma: Thanksgiving meals often consist of heavy, rich, and calorie-dense foods like turkey, stuffing, mashed potatoes, gravy, and desserts. Consuming a large quantity of such foods can lead to a phenomenon called "postprandial somnolence" or "food coma." When you eat a large meal, your body directs more blood flow to your digestive system to help process the food. This can temporarily reduce blood flow to other areas of your body, including your brain, which might contribute to feelings of sleepiness and lethargy.
• Carbohydrates and insulin: Many Thanksgiving dishes are carbohydrate-rich, such as mashed potatoes, stuffing, and pie. When you consume a lot of carbohydrates, your body releases insulin to help regulate blood sugar levels. This can lead to a drop in blood sugar levels after the initial spike, which may contribute to feelings of fatigue.
• Alcohol consumption: Thanksgiving is also a time when many people enjoy alcoholic beverages. Alcohol is a depressant that can have a sedative effect on the central nervous system, leading to feelings of tiredness or drowsiness. 
• Social and emotional factors: Thanksgiving gatherings often involve a lot of social interaction, preparation, and sometimes stress. These factors, combined with the act of consuming a large meal, can be emotionally and mentally draining, contributing to a feeling of tiredness.

Managing sleepiness on Thanksgiving Day without avoiding the turkey

If you’re usually exhausted at the end of the day, fear not. You have options. Here are some ways you can enjoy your turkey and stave off some of the sleepiness:

• Stay active: Engage in physical activity before or after your meal. A brisk walk, light jog, or even some stretching can help stimulate blood flow, boost your energy, and aid digestion.
• Hydrate: Drink plenty of water throughout the day. Dehydration can contribute to feelings of fatigue, so staying hydrated can help you stay more alert.
• Limit alcohol: If you choose to consume alcohol, do so in moderation. Excessive alcohol intake can exacerbate feelings of drowsiness.
• Break up the meal: Instead of eating one large meal, consider having smaller, more frequent meals throughout the day (if possible). This can help avoid a sudden spike in blood sugar followed by a crash.
• Balance the protein with fiber: Incorporate both protein-rich foods and high-fiber foods (like vegetables) into your meal. These can help stabilize your blood sugar levels and keep you feeling fuller and more energized.
• Avoid overeating: It can be tough on a holiday, but try to listen to your body's signals of fullness and avoid the temptation to overindulge. Overeating can lead to a larger release of insulin, potentially causing a drop in blood sugar and subsequent tiredness.
• Take short breaks: If you're involved in cooking or other preparations, be sure to take short breaks and rest to conserve your energy.
• Optimize your sleep: Leading up to Thanksgiving, try to maintain a regular sleep schedule to ensure you are well-rested before the big meal.
• Natural light exposure: Spend some time outdoors during the day, especially in natural sunlight. Sunlight helps regulate your body's internal clock and can improve alertness.
• Stay engaged: Engage in stimulating conversations and activities with family and friends. Keeping your mind active can help ward off feelings of tiredness.
• Caffeine in moderation: If you're a coffee or tea drinker, having a small amount of caffeine can provide a temporary energy boost. Just be cautious not to consume too much, especially if you're sensitive to caffeine.
• Mindful eating: Pay attention to your food while eating and savor each bite. This can help you feel more satisfied and prevent overeating.
• Manage stress: Thanksgiving preparations and gatherings can sometimes be stressful. Practice relaxation techniques like deep breathing, meditation, or mindfulness to help manage stress and maintain energy levels.

Enjoying turkey without the drowsiness

In summary, tryptophan is an amino acid that serves important roles in the body's biochemical processes, including producing neurotransmitters like serotonin. While it is present in foods like turkey, its effects on sleep and mood are influenced by a variety of other factors.

By managing these other factors, you can enjoy a more invigorating Thanksgiving Day.